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Photorefractive performances of a graphene-doped PATPD/7-DCST/ECZ compositehttp://hdl.handle.net/2289/6331
Title: Photorefractive performances of a graphene-doped PATPD/7-DCST/ECZ composite<br/><br/>Authors: Chantharasupawong, Panit; Christenson, Cory W; Philip, Reji; +5 Co-authors<br/><br/>Abstract: Photorefractive polymer composites have gained considerable attention due to their fascinating applications like 3D displays and 3D Telepresence. In this report, the performance of a novel PR polymer composite doped with graphene is studied. The addition of graphene laminates to a photorefractive composite results in up to threefold enhancement of space charge (SC) field build-up time. From our optical and electrical measurements, the faster build-up time is attributed to larger charge generation resulting from electronic interaction between graphene and the 7-DCST chromophores.<br/><br/>Description: Restricted Access.Ensemble effect of intrinsic defects and Mn ions on the enhancement of third order nonlinearity of ZnO nanoparticleshttp://hdl.handle.net/2289/6309
Title: Ensemble effect of intrinsic defects and Mn ions on the enhancement of third order nonlinearity of ZnO nanoparticles<br/><br/>Authors: Dhanuskodi, Sivasubramanina; Rajeswari, Ponnusamy; Sreekanth, P.; Philip, Reji<br/><br/>Abstract: Mn doped ZnO nanoparticles were synthesized by the chemical co-precipitation method and XRD confirms the hexagonal structure of nanoparticles with good crystallinity. From TEM analysis, the average crystallite size of the nanoparticles is evaluated as 7–13 nm. All the prepared nanoparticles exhibit reverse saturable absorption in open aperture Z-scan measurements. The experimental data best fits for two-photon absorption along with saturable absorption and the obtained β values are found to be in the range of 0.3–0.5 × 10−10 m W−1. The enhancement of β upon increasing Mn concentration is attributed to the increase of absorption due to defect states created by Mn doping. EPR and PL measurements provide evidence of the presence of zinc vacancy defects. The self-defocusing nonlinearity exhibited in Mn doped ZnO nanoparticles at 532 nm indicates the reverse saturable absorption (RSA) based optical limiting behavior.<br/><br/>Description: Restricted Access.Nonlinear optical investigations in nine-atom silver quantum clusters and graphitic carbon Nitride Nanosheetshttp://hdl.handle.net/2289/6301
Title: Nonlinear optical investigations in nine-atom silver quantum clusters and graphitic carbon Nitride Nanosheets<br/><br/>Authors: Sridharan, Kishore; Sreekanth, P.; Park, Tae Joo; Philip, Reji<br/><br/>Abstract: Absorption saturation due to surface plasmon resonance affects the optical limiting efficiency of metal nanoparticles (NPs) by raising the limiting threshold to higher laser fluences. It has been shown that in gold, compared to the larger NPs, smaller quantum clusters (QCs) exhibit better optical limiting with lower limiting thresholds due to the absence of absorption saturation. Here we report optical limiting properties of two novel materials, namely, nine-atom silver (Ag9) QCs and graphitic carbon nitride (GCN) nanosheets. The relatively large nonlinear absorption of Ag9 QCs compared to Ag NPs is revealed from open-aperture Z-scan measurements carried out using 532 nm, 5 ns laser pulses. Optical nonlinearity in the QCs arises mostly from free carrier absorption and a relatively weak saturable absorption. The superior limiting efficiency of Ag9 QCs is complemented by excellent chemical stability, which makes silver quantum clusters ideal candidates for optical limiting applications. The two-dimensional sheet-like structure of GCN is ideal for grafting metals and semiconductors, and we show that even though the nonlinearity of pristine GCN is low it can be improved substantially by grafting lightly with Ag9 QCs<br/><br/>Description: Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)Joint measurability and temporal steeringhttp://hdl.handle.net/2289/6297
Title: Joint measurability and temporal steering<br/><br/>Authors: Karthik, H.S.; Tej, Prabhu J.; Usha Devi, A.R.; Rajagopal, A.K.<br/><br/>Abstract: Quintino et al. [Phys. Rev. Lett. 113, 160402 (2014) [CrossRef] ] and Uola et al. [Phys. Rev. Lett. 113, 160403 (2014) [CrossRef] ] have recently established an intrinsic relation between nonjoint measurability and Einstein–Podolsky–Rosen steering. They showed that a set of measurements are incompatible (i.e., not jointly measurable) if and only if they can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result, viz., a set of measurements are incompatible if and only if they exhibit temporal steering in a single quantum system.<br/><br/>Description: Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)